Hi !
Do a search in the group for Takis and Karl´s posts regarding "autotune failure", starting september 2008.
You probably have to replace some caps on the voiceboards now.
One of Karl´s posts in copy here:
Hi Takis,
The other caps are Cx33 and Cx37 with x being 2,3,4,5,6,7 for each
voice respectivly. And Yes they are the same 2.2uF 50V Make sure they
are 50V rating. and correct polarity (You probobly knew that)
But before you replace those, try this.You are saying you are having
problems with all the voices right?
This points to the main DAC/Tuming circuit as you have already
guessed.
I would look closely at:
U811 The DAC
U816,U805 Multiplexer 4051
U812,U815,U813 Op Amps TLO81,TLO84,
TLO81
U814 Analog Switch 4053
Any of these parts failing could cause tuning problems like you
describe.
Now, before you replace them carfully pull them from the sockets and
re-seat them. Sometimes corrosion on the socket/chip lead can cause
a "not to good" connection. Also before I replaced them I would
reflow the solder on the bottom of the board, as bad solder joints
could also cause this.
If this does not work replace em. All except the DAC are readily
available. I would wait till you replaced the other chips before you
went searching for this DAC to see if any others are the cause. If
one of the chips have failed, I would bet on the mux or analog switch.
It would not hurt to replace the capacitors I mentioned above, as
they are probobly on their way out anyway.
Let Me Know How It Goes
Karl
mursupeppe schrieb:
Hi there, I wonder what could be a problem with the Matrix 12 when everything else's tuning well - except RES? Filter chips should be okay. It seems to "think" for a while whilst tuning RES on voices 3 and 5, and after the tuning cycle is complete, "FAIL" appears.
Any ideas? Should we just re-check everything or are there any specific areas in which the probable source of this problem exists?
Thanks,
-P.